I've got a '16 Silverado 1500 4wd L86/8L90.
So there's a low octane table and a high octane table. If I understand it correctly, excessive knock count causes the timing table to drop down to low octane, right? But how does it know when to revert back to the high octane table? Does it revert after a fill-up? Random timing test to see if it knocks?
I ask because I simply don't want to pay for 93 octane. It's usually 50-60 cents more/gallon and that means I'd spend about $60 extra/month. My thoughts are to blend in some E85, which is even cheaper than generic 87 around here. 8 gallons of E85 and 18 gallons of E10 87 would yield approximately 91 octane (assuming 100 octane E85) and 33% ethanol.
Without having a FF sensor and tuning adjusted, shouldn't the fuel trims adjust on their own? I realize the full potential wouldn't be met until timing is adjusted properly, but since the knock capacity has been increased wouldn't it be running higher timing than on 87 alone?
Thanks in advance!